Fluororesins are excellent in such properties as heat resistance, chemical resistance, and anti-stick properties and therefore used in a variety of applications. Various attempts have been made to modify fluororesins, which have such inherent excellent properties.
Patent Literature 1 teaches that incorporation of polytetrafluoroethylene which has a crystallization temperature of 305° C. or higher and a heat of crystallization of 50 J/g or higher into a melt-processable tetrafluoroethylene/fluoroalkoxytrifluoroethylene copolymer (PFA) composition, which is excellent in such properties as heat resistance and chemical resistance, markedly improves surface smoothness of a melt-excluded product of the PFA composition without impairing the properties of the PFA.
Patent Literature 2 teaches that a molded product of mixture of a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (A) and a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (B) that contains less perfluoro(alkyl vinyl ether)-derived polymer unit than the copolymer (A) has a reduced spherulite size and a smooth surface while maintaining inherent physical properties and formability of the PFA.
Patent Literature 3 discloses a method of producing a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer composition. The method includes copolymerization of tetrafluoroethylene and a perfluoro(alkyl vinyl ether) in a medium which contains a perfluoropolymer dispersed therein. Here, the perfluoropolymer comprises at least one selected from the group consisting of a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (A) and a tetrafluoroethylene polymer (B), and has a volumetric flow rate (X) of 0.1 mm3/sec or higher. This copolymerization yields a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (C) that contains more polymer units based on the 0.15 perfluoro(alkyl vinyl ether) than the copolymer (A), so that a composition comprising a mixture of the perfluoropolymer and the copolymer (C) is obtained. A PFA molded product obtained from this composition has a smaller spherulite size and a smooth surface while maintaining the inherent properties and formability of the PFA.
Patent Literature 4 teaches that a melt-molded product of a mixture of a melt-processable crystalline fluorine-containing resin with an amorphous fluorine-containing polymer or with a fluorine-containing multi-segmented polymer that contains an amorphous fluorine-containing polymer chain segment has a very smooth surface and decreases the probability of particle generation.
Patent Literature 5 teaches that a molded product of a mixture of a crystalline PFA with an amorphous fluorine-containing polymer has an improved surface smoothness and an improved transparency.
Patent Literature 6 teaches that incorporation of fluorinated diamond-containing particles into a fuser outer layer material containing a fluororesin allows a coating film that forms the outermost layer of a fuser component to have improved mechanical properties, surface abrasion resistance, and life.